The etching of oxide layers or films on the surface of semiconductor wafers is an important aspect of the manufacture of IC chips. Much of such wafer processing is performed using a wet etching process in which combinations of liquid acids and other chemicals and deionized ("DI") water and DI water alone are alternately sprayed onto wafers respectively to etch, clean and rinse the wafers. In addition, the wafers are periodically sprayed with nitrogen gas for drying the wafers. Typically, each wafer is confined in a wafer carrier made of a suitable acid-resistant material. One or more such wafer carriers are carried on a variable speed turntable or rotor in a closed bowl of a spray process tool, which tool may be programmed with respect to certain phases of its operation, including the rotational speed of the rotor, the order in which the liquid chemicals, DI water, and nitrogen gas are applied to the wafers and the temperature of the chemicals and DI water.
One such spray process tool is the MERCURY.RTM. MP, which is commercially available from FSI International, Chaska, Minn. The MERCURY.RTM. MP is a multi-cassette spray tool that can be configured to perform a variety of semiconductor wet chemical processing operations, including resist removal and prediffusion cleans using a combination of sulfuric acid and hydrogen peroxide (SPM clean), oxide etching using hydroflouride/DI water ("HF/DI") mixtures, and variations on the conventional RCA clean developed by RCA Corporation, Princeton, N.J.
The technology underlying semiconductor spray process tools has attracted increased attention over the last several years, resulting in substantial refinement thereof. However, despite the significant advances made in this area, many of the spray process tools that are currently commercially available suffer certain striking deficiencies. In particular, such tools lack advanced process data monitoring capabilities, such as the ability to provide historical parametric data in a user-friendly format, as well as event logging, real-time graphical display of both current and the entire run's process parameters, and remote, i.e., local site and worldwide, monitoring. These deficiencies can engender nonoptimal control of critical process parameters, such as chemical flow rate accuracy, stability and repeatability, process temperatures and mechanical tool parameters. This variability manifests itself as within-run, run-to-run and tool-to-tool disparities that can propagate into deviations in product quality and performance, whereas an ideal monitoring and diagnostics system for such tools would provide a means of monitoring this variability, as well as providing means for optimizing control of critical parameters.
Another disadvantage suffered by currently available tools is that they have a limited display, typically capable of displaying only a few lines of information, thereby limiting the utility thereof
Therefore, what is needed is a system for providing integrated monitoring, control and diagnostics functions for use with semiconductor spray process tools.